Fault phenomenon: After the second boot, the screen shows a raster but automatically shuts down before it fully loads. Pressing the standby button again causes the power to turn off for a moment, and the fault reappears.
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Repair process: At startup, voltages such as B1 (130V), filament voltage, video discharge voltage, +8V, +5V, ±14V are normal. However, during the second startup and standby mode, the 3rd pin (field protection input) of the 8879CSBNG6K02 measures 4.7V. Normally, this pin should be high in standby mode. After the second boot, it drops to 0V, indicating that the TV has entered a protection state.
Further inspection was done on Q015 (TC144E) connected to the 3rd pin of the 8879CSBNG6K02, focusing on the components connected to its B terminal. It was found that R030 (18K1/8W) was open-circuited. This resistor was replaced with a 20K1/4W one. After testing, the issue was resolved. R030 is connected to the deflection yoke through C025 (10uF50V).
The following circuit diagram was drawn based on the board: